Advanced Materials Research Vols. 189-193

Abstract: Traditionally, three CT markers are attached to a surgical guide of dental implant surgery to correlate the implant positions in CT images and the drill positions of a drill press. To allow the drill press to know the positions of the CT markers, users need to use the press to probe the positions of them manually. This process is inaccurate and time-consuming. The objective of this research was to develop a new process to eliminate the traditional probing process. This new process uses two identical pairs of locating pins both in the plaster mold cavity and on the fixture of a CNC drill press, respectively. Since the position of the drill bit relative to the locating pins and the positions of the locating pins relative to the CT markers are designed by us, the drill press knows the positions of the CT markers without probing them. According to the preliminary evaluation results, the mean errors of the location and angle of the drilled holes were 0.696 mm and 1.23°, which indicate that this innovative idea presented in this paper is feasible and promising.

Abstract: In the Na₂SiO₃-NaOH-C₃H₈O₃ electrolyte system,the micro-arc oxidation (MAO) coatings were prepared on AZ31 magnesium alloy when J=2A/dm²,4A/dm²,8A/dm² and 12A/dm².The relations of current density with microstructure and performance of the MAO coatings on AZ31 were studied by means of SEM, XRD, HVS-1000 micro Vicker, MFT-4000 Scratch Tester and electro-chemical method. The results show that when current density increases,the thickness,growth rate,micro-hardness and the contents of MgO and Mg₂SiO₄ of MAO coatings increase,but the adhesion force between MAO coating and substrate decreases, the millipores and the roughness become larger.The corrosion resistance of MAO coatings increases firstly and then decreases with the increasing current density.The corrosion resistance of MAO coating,which J=6 A/dm²,is the best in 4.5% NaCl water solution,whose corrosion current density reduces by 3 orders of magnitude, and corrosion potential increases 1078mV in positive direction.

Abstract: The original adjustment process of anti-surge control of the centrifugal compressor seriously wastes energy, and the traditional PID control is difficult to obtain satisfactory results. This paper designs an integral separation PID controller, the method can eliminate the integration accumulation on the one hand, and can take full advantage of integral control to eliminate static error and improve control precision on the other hand. Simulation results show that the method improves the optimization performance and the system dynamic performance is further improved.

Abstract: HIPIB irradiation experiment is carried out at a specific ion current density of 1.1 J/cm2 with shot number from one to ten in order to explore the effect of shot number on electrochemical corrosion behavior of magnesium alloy. Surface morphologies, microstructure and corrosion resistance of the irradiated samples are examined by scanning electron microscopy (SEM), transmission electron microscope (TEM) and potentiodynamic polarization technique, respectively. It is found that HIPIB irradiation leads to the increase in open circuit potential, corrosion potential and breakdown potential, and the decrease in the corrosion current density and the corrosion rate as compared to the original sample. The improved corrosion resistance is mainly attributed to the grain refinement and surface purification induced by HIPIB irradiation.

Abstract: A new technique was proposed for preparation of LaNi5 powder by direct electrolytic deoxidation of solid La₂O₃–NiO mixture oxides in molten CaCl₂–NaCl. Oxides pellets was sintered and used as cathode. High – density graphite was used as anode. Electrolysis was performed. Current change during electrolysis was recorded. XRD was used to analyse the composition of products. SEM was used to analysis surface and cross section of pellets before sintering, after sintering and after electrolysis. The preparation mechanism and the influences of sintering temperature and cell voltage on electrolytic deoxidation was studied. Results show that the optimum conditions to prepare LaNi₅ are：NiO-La₂O₃（Ni:La=5:1）pellets are formed at 30MPa, sintered at 850°C for 5h, electrolyzed under 3.2V in CaCl₂–NaCl melt at 850°C for more than 12 hours.

Abstract: Simulating current sintering process used by the brickkiln, at 800 °C, i.e. calcination temperature of the marginal area of the brickkiln, this work conducted experimental research on preventing sintering bricks of purple sandy shale from lime brust through fixing free CaO in sintering bricks with sulfur of high-sulfur coal. It is concluded that the critical content of CaCO₃ in purple sandy shale, causing lime brust of sintering bricks, is 24% by weight, when it is below this, lime brust commonly doesn’t occur; sulfur of high-sulfur coal (if necessarily, adulterated with pyrite ore) may effectively lower the concentration of free CaO in sintering bricks, accordingly eliminate or weaken lime brust; in condition of current market price of pyrite ore, the sintering process fixing free CaO with sulfur in pyrite ore is economically feasible.

Abstract: This paper used the pressure sensitive paints(PSP) as the experimental object, the organic silicon type of the 9801 is selected as one of the best binder. Fluorescence characteristics and oxygen quenching coefficient were studied on PSP with different pyrene contents. The result shows that the fluorescence intensity in Monomer Emission is gradually reduced with the increase of the content of pyrene in paint, but the fluorescence intensity in Excimer Emission is gradually increased. With the increase of the content of pyrene in PSP, oxygen quenching coefficient shows a normal distribution, it can be up to 21%.

Abstract: During the rolling process of big size parts, crinkle and hollows often appear in the surfaces. The reason of producing the defects is that the motions of the rolling mill tool are not consistent with the deformation of the part. On the basis of the principle of radial-axial ring rolling, a dynamics model is put forward. The relationship between part deformation and motion parameters is set up. The stress and strain of the part are simulated in the Finite Element Method by DEFORM software. A ring rolling process curve is defined. The rolling process is controlled by the curve. It is able to make the deformation of the part be consistent with the process parameters, and improve the product quality.

Abstract: The article introduces the processing technology of outside surface galvanized and inside surface plastic-coated steel for the main gas pipe line. It shows a better processing technology through the contrast, the quality of the membrane of the hot-galvanized steel pipe of inside surface coated LLDPE under the condition of special phosphorization process is equal to that as the result of rotoblasting technology. At the same time, anti-corrosion effect is better than before because of multi-layered and differently plated coatings. A Y-interface technology of independent intellectual property rights is used in interface.